Assessment of Soil Quality for a Semi-Arid Irrigated Under Citrus Orchard : Case of the Haouz Plain, Morocco

The irrigated perimeter of the Haouz plain is one of the largest in Morocco with 310.000 Ha with intense agricultural practices based on irrigation. Besides, recent studies have shown that the aquifer is characterized by an overall average to low sensitivity and vulnerability. The objective of this study is to provide an in depth diagnosis of the current situation regarding soil quality for a drip irrigation area: a citrus orchard, in a farm named Agafay, is located in the western part of Haouz, at 35 km SW of Marrakesh. To this objective, an intensive in situ campaign has been carried out focused on the measurements of the physico-chemical parameters of soil, at nine plots. The variation of these parameters, their impact on the type of rootstock and the variation of pollutants through the five soil horizons are analyzed. The results revealed that the condition in the soil quality is not very alarming. As most of the soils are light-textured, with poor organic matter content and basic to very basic pH. The reduction of organic matter, salinity, orthophosphates and nitrates with depth is attributed to the localized mode of irrigation adopted at the site which minimizes the loss of nutrients and, in fine, pollution of the aquifer. Multivariate analysis shows that the total and lime correlate well with the pH, which in turn correlate negatively with nitrate content and soil electrical conductivity. This work has strong implications for the quality assessment of soil for all irrigated perimeters by the drip in semi-arid areas, order to ensure the conservation and sustainability of the production system

Trends in flow intermittence for European rivers

Intermittent rivers are prevalent in many countries across Europe, but little is known about the temporal evolution of intermittence and its relationship with climate variability. Trend analysis of the annual and seasonal number of zero-flow days, the maximum duration of dry spells and the mean date of the zero-flow events is performed on a database of 452 rivers with varying degrees of intermittence between 1970 and 2010. The relationships between flow intermittence and climate are investigated using the standardized precipitation evapotranspiration index (SPEI) and climate indices describing large-scale atmospheric circulation. The results indicate a strong spatial variability of the seasonal patterns of intermittence and the annual and seasonal number of zero-flow days, highlighting the controls exerted by local catchment properties. Most of the detected trends indicate an increasing number of zero-flow days, which also tend to occur earlier in the year, particularly in southern Europe. The SPEI is found to be strongly related to the annual and seasonal zero-flow day occurrence in more than half of the stations for different accumulation times between 12 and 24 months. Conversely, there is a weaker dependence of river intermittence with large-scale circulation indices. Overall, these results suggest increased water stress in intermittent rivers that may affect their biota and biochemistry and also reduce available water resources

Les tracages d'essai en aquifere heterogene: methodes, interet et limites. Application au milieu alluvionnaire Languedocien et comparaison avec les milieux carbonates et fissures du Nord de la France

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 81899 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Impacts de la variabilité climatique et anthropique sur les ressources en eau du bassin versant du Tensift – Maroc

International audienc

Flood modeling of the 21-23 November 2014 events in the High-Atlas Mountains (Morocco).

International audienceThe catchments located in the High-Atlas Mountains of Morocco are providing most of the surface water resources for the Tensift basin around Marrakech, but due to their steep slopes and limited vegetation cover they are also subjected to severe flood events. This study is focusing on the Ourika (502km²) and the Rheraya (225km²) catchments, with altitudes ranging between 1000m and 4000m. In august 1995, a thunderstorm with a maximum intensity of 100mm/h caused a peak discharge of 1070m3.s-1 causing several deaths and damages. Following this event, from 2002 to 2012 a real-time telemetered monitoring network has been setup in the Ourika and the Rheraya catchments, to alert the population based on precipitation and discharge thresholds. In November 2014, several high-intensity rainfall events struck the southern regions of Morocco, including the Ourika and Rheraya catchments, and the data collected during these events is considered in the present work. The goal of this study is to move beyond the alert system towards the real-time modeling of floods, in order to provide short-term hydrological previsions based on measurements and meteorological forecasts, provided by Maroc-Météo with the Aladin-Bachir and Arome models. The first results are here presented, trying to answer three research questions: i) Is the magnitude or the occurrence of extreme floods changing with time? ii) Is the precipitation station network representative of the spatial variability of rainfall in these mountainous catchments? iii) Can hydrological models reproduce floods in an adequate manner in these complex catchments? These questions are addressed using the long-term (1962-present) discharge measurements available, together with hourly precipitation and discharge measured from the telemetered network for the year 2014 as inputs of global or distributed hydrological models. The results indicate no significant trends for the magnitude or the occurrence of floods in the catchments. Rainfall-runoff models are able to reproduce the floods that occurred in 2014 with a good accuracy, but strongly dependent on the structure of the models. A first evaluation of the meteorological forecasts is also presented

Future Scenarios of Surface Water Resources Availability in North African Dams

International audienc

Evaluation of satellite-based rainfall products for hydrological modelling in Morocco

International audienc

Flood modeling of the 21-23 November 2014 events in the High-Atlas Mountains (Morocco).

International audienceThe catchments located in the High-Atlas Mountains of Morocco are providing most of the surface water resources for the Tensift basin around Marrakech, but due to their steep slopes and limited vegetation cover they are also subjected to severe flood events. This study is focusing on the Ourika (502km²) and the Rheraya (225km²) catchments, with altitudes ranging between 1000m and 4000m. In august 1995, a thunderstorm with a maximum intensity of 100mm/h caused a peak discharge of 1070m3.s-1 causing several deaths and damages. Following this event, from 2002 to 2012 a real-time telemetered monitoring network has been setup in the Ourika and the Rheraya catchments, to alert the population based on precipitation and discharge thresholds. In November 2014, several high-intensity rainfall events struck the southern regions of Morocco, including the Ourika and Rheraya catchments, and the data collected during these events is considered in the present work. The goal of this study is to move beyond the alert system towards the real-time modeling of floods, in order to provide short-term hydrological previsions based on measurements and meteorological forecasts, provided by Maroc-Météo with the Aladin-Bachir and Arome models. The first results are here presented, trying to answer three research questions: i) Is the magnitude or the occurrence of extreme floods changing with time? ii) Is the precipitation station network representative of the spatial variability of rainfall in these mountainous catchments? iii) Can hydrological models reproduce floods in an adequate manner in these complex catchments? These questions are addressed using the long-term (1962-present) discharge measurements available, together with hourly precipitation and discharge measured from the telemetered network for the year 2014 as inputs of global or distributed hydrological models. The results indicate no significant trends for the magnitude or the occurrence of floods in the catchments. Rainfall-runoff models are able to reproduce the floods that occurred in 2014 with a good accuracy, but strongly dependent on the structure of the models. A first evaluation of the meteorological forecasts is also presented